Why Topping a Mature Honey Locust Is a Mistake

Your mature honey locust is thinning with dead branches. You’re considering topping to “rebound” it. Do not top. Topping a mature tree often kills it or creates dangerous, weakly attached regrowth.

What Topping Does

• Removes the leaf-bearing crown, starving the roots.
• Stimulates dense, poorly attached “watersprouts” prone to breakage.
• Creates large wounds that invite decay and borers.
• Destroys natural form and reduces lifespan.

Likely Causes of Decline

• Root disease, stem cankers, borers, soil compaction, drought stress, or old age.
• Honey locusts are prone to Thyronectria canker and mimosa webworm.

Better Approach

1. Diagnose: Hire an ISA Certified Arborist to identify the specific problem(s).
2. Fertilize: 10-10-10 at 1 lb/inch trunk diameter, scattered, watered in (before rain).
3. Borers: If trunk has wet, soft spots, spray with permethrin (Onyx) or imidacloprid.
4. Prune properly: Remove only dead, diseased, or crossing branches—back to branch collar.
5. Mulch and water during dry periods.

Bottom Line

Topping is tree abuse. Invest in diagnosis and targeted care. A professional can often extend a mature tree’s life by years.